This calculator works out stair risers, treads, run and slope geometry. Total rise is divided into whole risers and checked with tread depth to show a preliminary flight geometry. Replace the example values with information from your own label, bill, drawing, product sheet or land record. A qualified designer must check local code, headroom, landings, handrails, width and structural support. The formula and every editable assumption remain visible so the result can be checked before it is used for planning. Keep the values and result together when you compare or share this planning scenario.
This tool does not select slab thickness, reinforcement, bar schedule, stair geometry compliance or structural safety. Enter only dimensions and allowances approved for the project by a qualified professional.
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Every input includes a simple explanation.
Private: calculations run in your browser. Saved scenarios, preferred electricity rate and land state stay on this device.
Real site dimensions and workmanship affect the quantity.
Transport, cutting, pattern and breakage affect how much extra material to order.
This is an early quantity estimate. Site conditions, drawings, product details and workmanship can change the final requirement.
Read the meaning first, verify the important details, then avoid the most common planning error.
Total rise is divided into whole risers and checked with tread depth to show a preliminary flight geometry.
A qualified designer must check local code, headroom, landings, handrails, width and structural support.
Adjusting riser height without recalculating every equal riser creates an unsafe and uncomfortable stair.
Use this calculator only for an early quantity estimate. A qualified civil or structural engineer must decide the final structure, reinforcement and safety details.
Updated 17 July 2026. Changes listed here describe this calculator release; they are not invented historical entries.